Why do people in some cultures regularly carry heavy objects on their heads? It's because, biomechanically speaking, head-loading is an efficient means of hauling cargo:

Based on studies of women of the Luo and Kikuyu tribes of East Africa, researchers have found that people can carry loads of up to 20 percent of their own body weight without expending any extra energy beyond what they'd use by walking around unencumbered.

But don't strap gear to your head just yet. Head-loading only works well if you've been practicing it for many years:

The subjects in these studies began head-loading as children and had developed a peculiar gait that's one-third more efficient than the one we're likely to use.

For untrained controls who have not had years to strengthen the right muscles and build up spinal bone density, carrying things on your head actually requires more energy than using a backpack.

It is impressive to see though. I was in Tanzania last year and saw porters carry incredible loads on their heads. Crazy things too like huge crates of eggs, tables, and some really unfortunate fella who got stuck carrying a portable toilet on his head.

I never learned the fine art of asking for help,so I learned the head-carry a looong time ago. And good lord, you don't have to train for it - as long as you are able / know how to hold your neck stable, and have some common sense, you're good to go.